1. Field of the Inventions
The present inventions relate to a power transmitting apparatus for arbitrarily transmitting or cutting-off the rotational driving power of an input member to or from an output member.
2. Description of the Related Art
In general the power transmission apparatus for a motorcycle is intended to arbitrarily perform transmission or cutting-off of the driving power of an engine to or from a transmission and a driving wheel and comprises an input member connected to an engine-side, an output member connected to a transmission and a driving wheel-side, and a clutch member connected to the output member. The driving power can be transmitted by press-contacting a plurality of driving-side clutch discs and driven-side clutch discs with each other or cut off by releasing the press-contacting force acting on the driving-side clutch discs and driven-side clutch discs.
More particularly, the power transmitting apparatus of the prior art comprises a clutch housing rotatable together with an input member and mounted thereon a plurality of driving-side clutch discs, a plurality of driven-side clutch discs arranged alternately between the driving-side clutch discs, a clutch member connected to an output member, a pressure member mounted on the clutch member axially movably relative to the clutch member for forcing the driving-side clutch discs and the driven-side clutch discs to be press-contacted with each other and to release the press-contacting force acting on them in accordance with axial movement relative to the clutch member, and an intermediate member spline-fitted thereon with the driven-side clutch discs, and is constructed so as to transmit or cut-off the driving power inputted to the input member to or from the output member by press-contacting the driving-side clutch discs and the driven-side clutch discs with each other or releasing a press-contacting force acting on them.
Heretofore a power transmitting apparatus has been proposed provided with a back-torque limiting cam comprising a clutch member-side cam surface formed on the clutch member and an intermediate member-side cam surface formed on the intermediate member for performing a cam action so that the pressure member and the intermediate member are axially moved to release the press-contacting force acting on the driving-side clutch discs and the driven-side clutch discs when the rotational speed of the output member exceeds the rotational speed of the input member and a relative rotation is caused between the intermediate member and the clutch member (see, e.g., Japanese Patent Application JP 2011-153655 A).